A 47-year-old female with known metastatic breast carcinoma has been admitted to the oncology ward for investigation of increasing shortness of breath. A pulmonary embolism was suspected on clinical grounds and a CT pulmonary angiogram was performed. It failed to demonstrate any pulmonary emboli but did show a 2.2 cm global pericardial effusion. On the basis of this, a transthoracic echocardiogram was performed which ruled out tamponade.
Which one of the following statements is correct?
A. Breast carcinoma typically metastasizes to the pericardium but significant pericardial effusions are rareCardiac metastases occur via four routes:
Pericardial metastases typically arise from lymphatic spread whereas haematogenous spread preferentially gives rise to myocardial metastases. Endocardial tumour deposits are rarely found.
Owing to their location and prevalence, lung and breast carcinomas are the most common tumours causing cardiac metastases and both preferentially affect the pericardium, resulting in usually large effusions. Cardiac metastases are seen in around half the cases of metastatic melanoma.
Extracardiac tumours may reach the atria and ventricles by transvenous extension. Renal cell carcinoma growth through the inferior vena cava into the right atrium is thought to occur in up to 1% of cases. Rarely, bronchial carcinoma spreads through the pulmonary veins into the left-side heart cavities.
In cases of pericardial effusion causing circulatory embarrassment, pericardiocentesis is mandatory and may help diagnosis. Following pericardiocentesis, a constrictive picture often persists due to inflammation and thickening of the pericardium.